1. Field of the Invention
The present invention is broadly concerned with an improved slotter head assembly of the type used in boxmaking equipment for forming flap-defining slots in box blanks. More particularly, it is concerned with such a slotter head assembly which is improved by provision of a pressurized fluid-actuated mechanism for selectively locking the slotter blade knives in position, while permitting ready adjustment of the knife positions. In this fashion, the box blank slotting equipment can be readily altered to produce blanks of different configurations without the need for time-consuming manual knife adjustments. In preferred forms, the pressurized fluid-actuated mechanism includes an elongated, pneumatic bladder positioned adjacent the corresponding knife blades, and operable upon filling of the bladder to engage and lock the knives in place.
2. Description of the Prior Art
The manufacture of box blanks on an industrial scale normally involves slotting and creasing of precut corrugated sections, in order to create a blank having the requisite fold lines and flaps for a given box. Normally, the slotting equipment used for this purpose includes an elongated shaft carrying a plurality of annular rotatable slotter heads. Normally, a pair of slotting knives are secured to each head for rotation therewith. The circumferential spacing of the slotter knives thus determines the depth of the flap-defining slots for a given blank.
A persistent problem in the box-making industry stems from the time and effort required to change the position of slotting knives on the individual slotting heads. That is to say, after a given box blank run is completed, it is often necessary to change the circumferential location of the knives in order to produce in the next run blanks of different configuration. Generally speaking, prior art slotter heads are equipped with a series of threaded bores in the sidewall thereof, for attachment of the slotted knives by means of bolts. When it is necessary to change the location of one or more of the knives, it is necessary to remove the knife-retaining bolts, relocate the knife to a desire position, and reinstall the bolts. This practice can be relatively time-consuming, especially when it is considered that a number of heads need to be changed for each run. Moreover, the slotter heads are located within large blankforming equipment, and it is sometimes to difficult to gain access to the heads for knife changeover.
Accordingly, there is a real and unsatisfied need in the art for a simplified slotter head and knife arrangement which will allow quick knife adjustment without the need for removing and reinstalling bolts or other mechanical fasteners.